For a while, things looked good. The Blue Jackets took a 2-0 lead in the second period before allowing two goals to the Islanders before the end of the frame, setting the stage for an important third period.

Unfortunately, Columbus failed to get the win – much less a point – thanks to Casey Cizikas' game-winning goal at 7:09 of the third period. The goal was a coach's nightmare. It was so easy for noted goal-scorer Cizikas (in his eighth NHL season, he's never scored 10 or more goals in a season) to get open that it was obvious there was a blown assignment along the way.

A frustrated John Tortorella had this to say:

"And then we absolutely blow a simple coverage 4-on-4. It's man on man, and those little mistakes, it cost us."

Like virtually every goal in the NHL, somethingmaterializes from nothingquite quickly. The whole play happens between 0:00-0:07, so I added the applicable replay time stamps below as well.

Note that the play is 4-on-4, which has the simplest coverage in hockey. The reason: in 5-on-5, the Blue Jackets' center is a de facto defenseman in the defensive zone, since the Blue Jackets have two defensemen matching the other team's three forwards. At 4-on-4, the two Blue Jackets forwards match up against the Islanders' defensemen and the defensemen will take the Islanders' forwards.

Like Tortorella said, it's man-on-man coverage. Pretty simple stuff.

0:00-0:03: A seemingly innocuous start to the goal as the puck is worked around the perimeter of the zone. Ryan Pulock, No. 6 for the Islanders, has the puck and is skating down the boards. Not much to see...yet.

0:04-0:05 (0:46-0:47): This is where the play starts to take shape. In front of the net, Zach Werenski is guarding the eventual goal-scorer, Cizikas. Alexander Wennberg is high in the slot guarding the backside Islanders defenseman. Cam Atkinson is guarding Pulock (remember, Blue Jackets forwards should – and do – guard the Islanders defensemen here). Lastly, Seth Jones is well marked up on Jordan Eberle, No. 7.

0:06 (0:48): The announcer wonders aloud why Pulock didn't shoot the puck, since he's well-guarded and has a cannon of a shot. At this point, ignore everything north of the face-off dot and focus on Atkinson and Werenski. Pulock has a step on Atkinson but it's not yet a dire situation. Werenski is well-positioned between Pulock and Cizikas...for now.

0:07 (0:49): By now, you see Cizikas standing wide open in front of the crease. He's pretty much set up shop, and in the NHL, it's a rarity to find yourself this alone in such prime real estate. If you watch Werenski's stick, you'll see what went wrong. He over-commits to Pulock and is absolutely convinced that a cross-ice pass (or a shot) is imminent. But it never comes. And when Pulock comes out the other side, Werenski is late getting back to his check, Cizikas.

What Werenski did was almost admirable, if you will. He wanted to provide extra assistance to his forward playing defense (Atkinson). And if Atkinson catches up to Pulock, who isn't exactly a burner, and gets his stick on the passing lane, this isn't even a conversation. But this goal was clearly Werenski's man, and he abandoned the fort.

To give credit where it's due, Cizikas does exactly what any smart player should do: Put yourself in a position where you're available at the most dangerous time in as dangerous a location as possible. You'll note that he barely moved at all on this play, simply pivoting in front of the net to give Pulock an easy angle for a tap-in goal.

At the same token, this is as simple a blown coverage as you'll ever see in the NHL. It's man-on-man, and Werenski got caught helping Atkinson instead of taking his own man.